The parotid gland is the body’s largest salivary gland, situated in front of the ear with extension downward into the upper neck region. This location makes it the most frequent site for salivary gland tumours, with approximately 80% being benign. Most parotid lumps present without symptoms and are discovered incidentally by patients, or during imaging for other conditions. Rarely, pain or facial weakness may occur, which warrants concern. Any parotid lump needs specialist evaluation, including a thorough history, physical examination, ultrasound with biopsy, and MRI imaging.
Benign parotid lumps
- The pleomorphic adenoma is the most common parotid lump, and is non-cancerous. Though rare, these can occasionally undergo malignant transformation, making removal typically advisable.
- Adenolymphoma, or Warthin’s tumour, is the second most common benign tumour, occurring on both sides in 10% of cases. These may be observed or removed based on size and patient preference, as they do not become cancerous.
Cancerous tumours
Malignant tumours account for only 20% of parotid lumps, and comprise several subtypes. Cancerous findings are managed through a Head & Neck Multidisciplinary Team, with individualised treatment plans. Concerning symptoms include pain, overlying skin changes, rapid growth, and facial nerve weakness. Parotid cancers occasionally originate from other sites — head and neck skin cancers spreading to parotid lymph nodes are an example. Lymph node swelling within the parotid gland requires urgent evaluation, as it is highly suspicious.
Investigations to determine the diagnosis
All parotid lumps require MRI, ultrasound and core biopsy evaluation. The MRI assesses the lump’s characteristics, size, exact location and involvement of surrounding structures, while identifying any other neck or opposite-side gland lumps. Ultrasound-guided core biopsy, performed under local anaesthetic, obtains pathology samples for tumour classification. This combined approach achieves an accurate diagnosis in around 90 to 95% of patients. Suspicious lesions also receive a chest CT scan.
The procedure
Surgery proceeds as a day case, or with an overnight or two-night hospital stay when indicated. General anaesthesia enables either approach:
- An extracapsular lumpectomy removes only the lump, in non-cancerous cases.
- A formal parotid operation involves identifying the facial nerve and working above and below it to prevent damage, while removing the lump and a portion of the parotid.
Risks of parotid surgery
- Facial nerve damage is the primary risk, causing facial muscle weakness. This is usually temporary, with about 75% of weakness recovering, though permanent damage remains very rare.
- Scarring typically becomes less noticeable over time, and is often hidden within skin creases.
- Numbness affecting the earlobe and cheek occurs in at least 50% of patients, often persisting partially despite gradual improvement.
- Standard operative risks include wound infection, bleeding and seroma (a fluid collection).
- Frey’s syndrome causes cheek redness and sweating when eating; this is usually mild and resolves within one year, with reduced risk following a lumpectomy.
- Salivary fistula involves temporary saliva leaking into the neck, which typically settles quickly or requires needle drainage.
- Lump recurrence is an uncommon possibility.
- Facial contouring changes may occur with extensive parotid gland removal.
Post-operative information
A drain collects excess fluid, and is removed within 4 to 6 hours, or the following day. Skin sutures or clips require removal at the GP surgery 3 to 7 days after the procedure. A follow-up clinic appointment occurs approximately two weeks afterwards. Patients may contact the Practice Manager with any post-operative concerns.